FACEBOOK

The land surface is a key component of climate models. It controls the partitioning of available energy at the surfacebetween sensible and latent heat, and it controls the partitioning of available water between evaporation and runoff.The land surface is also the location of the terrestrial carbon sink. Evidence is increasing that the inﬂuence of the landsurface is signiﬁcant on climate and that changes in the land surface can inﬂuence regional- to global-scale climate ontime scales from days to millennia. Further, there is now a suggestion that the terrestrial carbon sink may decrease asglobal temperatures increase as a consequence of rising CO2 levels. This paper provides the theoretical background thatexplains why the land surface should play a central role in climate. It also provides evidence, sourced from climatemodel experiments, that the land surface is of central importance. This paper then reviews the development of landsurface models designed for climate models from the early, very simple models through to recent efforts, which includea coupling of biophysical processes to represent carbon exchange. It is pointed out that signiﬁcant problems remain to beaddressed, including the difﬁculties in parameterizing hydrological processes, root processes, sub-grid-scale heterogeneityand biogeochemical cycles. It is argued that continued development of land surface models requires more multidisciplinaryefforts by scientists with a wide range of skills. However, it is also argued that the framework is now in place withinthe international community to build and maintain the latest generation of land surface models. Further, there should beconsiderable optimism that consolidating the recent rapid advances in land surface modelling will enhance our capabilityto simulate the impacts of land-cover change and the impacts of increasing CO2 on the global and regional environment.Copyright  2003 Royal Meteorological Society.